Side-gusseted bag made of film

ABSTRACT

A side-gusseted bag ( 1, 22 ) made of film is disclosed, having two main walls ( 6, 7 ) and side-gusseted walls ( 8  to  11; 23, 24 ) lying therebetween on the periphery; said side-gusseted walls can be folded flat into a V-shape parallel to a longitudinal direction between two main walls ( 6, 7 ) lying on top of one another. The main walls ( 6, 7 ) encompass, in a head region ( 2, 28 ), a grommet ( 4, 33 ) with two opposing fastening surfaces for the film and the two sides of the grommet ( 4, 33 ) are also directly connected with one another in a head joint ( 5, 32 ). The side-gusseted bag is designed for complete filling as a liner in an outer container for production with standard machine means in such a manner that a plurality of side-gusseted walls ( 8  to  11; 23, 24 ) are arranged between the main walls ( 6, 7 ), at least on one side, and that the side-gusseted walls ( 8  to  11; 23, 24 ) are connected to one another or to the main walls ( 6, 7 ) in the head region ( 2, 28 ) and are bounded by diagonal seams ( 17, 18; 30, 31 ), which converge diagonally partially at one end and partially at the other end of a head seam ( 5, 32 ) bounded at a central region on both sides of the grommet ( 4, 33 ) with correspondingly spaced gusset lines ( 20, 21 ) of the side-gusseted walls ( 8  to  11, 23, 24 ).

The invention concerns a side-gusseted bag according to the preamble of claim 1. Side-gusseted bags of film, in particular plastic film, that are embodied in circumferential direction of two main walls and two intermediately positioned side-gusseted walls and are delimited at the top side and bottom side by transverse seams or reclosure devices are widely used in daily life. A side-gusseted bag for receiving pasty or liquid substances, even though with incompletely formed side gussets, is disclosed in EP 1 362 797 B1 wherein the bag at the topside is closed off by a transversely extending head seam into which a spout in the form of a cap closure is sealed. Spouts of this kind typically comprise a weld-in or seal-in region in which opposite fastening surfaces enable a fold-free contact of the film and an attachment that provides a load-resistant and seal-tight closure.

The type of the side-gusseted bag disclosed in the aforementioned publication is designed to provide transitions between the bag of film and the spout that are free of folds as much as possible. Even though, the known bag, due to its rectangular basic shape, tends to form a filling shape with gusset-shaped or pocket-shaped areas that counteract filling without air inclusions and emptying without liquid residues.

On the other hand, there is a significant interest in film packagings that are material-saving and are inert with regard to the liquid filling, that can be filled and emptied completely and without problems. Such containers are conceivable as individual containers as well as in the form of linings or inner bags for enclosing containers of the solid type, such as cardboard, wood or sheet metal containers, in which the inner container can be emptied by being collapsed and optionally also ensures exclusion of air in this context. This is utilized, for example, in connection with wine containers that with a large fill volume and correspondingly long emptying periods avoid detrimental effects on the wine due to exposure to air. At the same time, there is an interest in designing the manufacture of such side-gusseted bags by means of machines so as to be reliably moisture-tight and breakage-safe and in particular also inexpensive.

It is therefore the object of the invention to redesign a side-gusseted bag as a closed container provided with a spout such that, as a liquid container, it is suitable for complete filling and complete emptying while, at the same time, it can be produced by conventional manufacturing methods and in manufacturing machines in an uncomplicated, fast and breakage-safe way, wherein the shape should also be collapsible to a flat state for a compact arrangement for shipping and storage.

According to the invention, this object is solved by a side-gusseted bag, based on the preamble of claim 1, with the characterizing features of claim 1. While the conventional four-sided side-gusseted bag is designed to obtain, upon filling, for example, with grainy material, a parallelepipedal shape that, however, upon filling with liquid would bulge and distort and also generate corners and pockets, an increase in the number of sides is already suitable to provide a multi-sided polygon shape and thus a better approximation to a desired rounding of the circumference. In comparison to a four-sided or square cross-section, already a pentagon cross-sectional shape matches much better a circular shape that is formed at least in approximation due to interior pressure of a liquid. The increase of surfaces is achieved by a greater number of side-gusseted walls that, as in the conventional four-sided side-gusseted bag, can assume a flat arrangement with main surfaces and intermediately folded-in sidewalls.

In this context, an increase of the number of sidewalls for reasons of simple two-sided manufacture as well as uniform folded position of the side-gusseted bag, two side-gusseted walls each underneath each side of the main walls will be preferred in order to achieve a better rounding with a hexagon cross-sectional shape as compared to a pentagon cross-sectional shape. In the same sense, even higher wall numbers can be provided also whereby however the manufacturing expenditure then also becomes greater without the approximation of the polygonal contour to a round cross-section being increased equally.

Slanted seams between the side-gusseted walls among each other or between the side-gusseted walls and the main walls that provide at least the head region on the inner side with a geometry in the form of a smooth cover wall contribute significantly to avoiding accumulations or pockets upon filling or emptying of such a side-gusseted bag. For adaptation to a container with flat bottom and top surfaces, such a cover wall can be predetermined to be planar. However, it is also possible with smaller angles of the slanted seams relative to the longitudinal direction to orient the configuration of the inner shape in the head region to extend conically toward the spout in order to ensure a complete and easy inflow and outflow.

U.S. Pat. No. 7,147,597 B2 discloses already side-gusseted bags with (three or) five circumferential sides which however are not collapsible to a flat and smooth state. Here, all slanted seams in the head region are oriented toward a single center point in order to connect a spout with all circumferential sides. These connections cannot be produced easily on a machine and lead to wall transitions that cannot be folded in so as to be free of wrinkles.

A side-gusseted bag according to the invention made of film can be produced in a particularly simple way by means of sealed seams when the film as a whole is sealable or is provided at least on one side with a sealable layer. Conventionally used and well suited in this context is a composite film with a polyolefin film, in particular polyethylene, as an inner layer that provides excellent sealability on the inner side and an outer layer of polyester which is usually thinner, stronger, and is also melting at higher temperature. This material combination has also the further advantage, widely used in practice, that the sealed seams between the side-gusseted walls among each other and between the side-gusseted walls and the main walls can be sealed, while resting on each other, through several films in one single working step without thereafter the outer sides being fused together and preventing unfolding of the bag from its flat position into the fill position.

It is understood, of course, that, depending on the requirements in regard to seal-tightness and chemical resistance, also adhesively connectable or fusible metal films or also composite films with a metal layer can be employed instead of the plastic composite film.

Manufacture of such a side-gusseted bag is possible on machines that manufacture already conventional side-gusseted bags with two main walls and only two side-gusseted walls positioned individually therebetween. Manufacture is first directed at a hose (circumferentially closed) that can be produced in that a single film web has the oppositely positioned lateral edges combined and closed by a single longitudinal seam to form a hose, but also, in an alternative conventional embodiment, in that the main walls and the side-gusseted walls as strips are combined and connected to each other by several longitudinal seams to form a hose. In conventional side-gusseted bags, slanted seams as support seams have already been used partially at 45° relative to the longitudinal direction which, however, usually did not delimit the side-gusseted walls but only shape them internally. For a large number of side-gusseted walls according to the invention, the slanted seams extend however typically at an angle of less than 45° relative to the longitudinal direction.

The more precise determination of the angle is realized with respect to whether a flat planar head region, for adaptation to an enclosing container with a flat top side, or a funnel-shaped head region for better complete filling and emptying is to be provided. In case of the flat planar head design the slanted seams of the unfolded side walls and main walls in the head plane form triangles that combine to a planar surface. In deviation from a uniform division of a pentagon, hexagon, or polygon by identical inwardly converging triangles, it must be taken into consideration that two oppositely positioned walls are to abut not with a point but with an at least short head seam into which also the spout is to be incorporated. Accordingly, typically two larger triangles with a cut-off tip for the head seam are to be provided opposite each other which usually are provided for the main walls wherein the slanted seams begin to diverge only from the two ends of the head seam.

The afore described configuration basically also applies to an embodiment of the side-gusseted bag that is conical or funnel-shaped in the head region wherein the triangular shapes of the walls wipe the slanted seams are all the more pointed the more pronounced the conical shape is to be designed.

Aside from all the freedom of design, a configuration of the side-gusseted walls with identical circumferential width relative to each other is particularly self-evident where the neighboring side-gusseted walls in the folded-in state also are positioned congruently on top of each other while the main walls have a width that is longer by the length of the head seam.

The main walls and the side-gusseted walls can be provided with longitudinal seams between each other when manufacture of the side-gusseted bag is based on a single film web and therefore only a single longitudinal seam would have to be provided. Longitudinal seams between the main walls and the side-gusseted walls or between the side-gusseted walls among each other can however be expedient for stiffening the bag and for a controlled collapse upon emptying. Preferably, the longitudinal seams are then provided as fin seams that project outwardly. This makes it possible to keep the inner side of the side-gusseted bag smooth and without unnecessarily wetted surfaces. The fin seams which are projecting outwardly are desirable also for side-gusseted bags to be used as inner container and which thereby counteract an undesirable adhesion of the inner container on the exterior container.

The configuration of a bottom region, that is oppositely position to the head region at the bottom, can be realized with very similar considerations wherein however a central head seam is not needed because at the bottom usually no spout or other emptying opening must be provided. Accordingly, also in the bottom area acute-angled triangles can be provided between slanted seams. Preferably, the bottom area in consideration of a smooth collapse of the bag is designed congruent with the head region. The “congruent” configuration of the bottom area relative to the head region does not prevent to design indeed the bottom to be flat when the head region is conically extended, and vice versa.

The usual terms of “head” or “bottom” relate theoretically to a (fill) position with spout at the topside even when the bag for emptying must be positioned upside down.

Two embodiments of the invention are illustrated in the drawing and will be explained in the following in more detail. The drawing shows in:

FIG. 1 side view of a first embodiment (partially broken),

FIG. 2 plan view of the embodiment according to FIG. 1,

FIG. 3 cross-section of the embodiment of FIG. 1 and FIG. 2 at the beginning of folding,

FIG. 4 enlarged detail IV of FIG. 3,

FIG. 5 cross-section of the side-gusseted bag in folded state,

FIG. 6 plan view of the folded state according to FIG. 5, and

FIG. 7 side view of a second embodiment of the side-gusseted bag.

In FIG. 1 and FIG. 2 a side-gusseted bag according to the invention in unfolded state is identified with 1. It has a hexagon contour comprised of six walls that in regard to width to not deviate or only insignificantly deviate from each other, which adjoin each other in the circumferential direction and converge toward a head region 2 as well as toward a bottom 3 toward the center. The head region is provided with a spout 4 at the center.

The side-gusseted bag 1 is embodied of a film that is sealable at the inner side, in the present case a plastic composite film with a polyethylene (PE) inner layer and a polyester (PET) outer layer. Into this film, the spout 4 is sealed seal-tightly and fixedly into a head seam 5 by means of two oppositely positioned sealing surfaces as fastening surfaces. The illustrated spout can be closed by a screw cap, but of course could also be provided with a stopper or another closure.

The side-gusseted bag 1 that unfolds substantially to a drum shape has a hexagon contour for filling with liquid, where upon it approximates a cylindrical shape, formed by side walls joined to each other which in the head region 2 and at the bottom 3 similar to pie slices converge toward the center. However, they do not meet at a single central point but meet at one of two ends, respectively, of the head seam 5 that enables the two-sided sealing of a spout. The head seam 5 is formed between the upper cut-off triangular tips of two walls 6, 7 that are provided somewhat wider than the other walls 8, 9, 10, 11 in order to adjust the geometry of the lateral lengths and angles relative to each other. In principle, however, sides of the same circumferential width can be provided also as long as in the head region the arrangement of a spout is ensured.

FIG. 3 shows the sides 8, 9, 10, 11 extending parallel and slightly bent to a longitudinal direction that is to be imagined to extend centrally from the bottom 3 to the head region. This indicates that these walls are to be understood as side-gusseted walls that enable folding of the side-gusseted bag as in case of conventional side-gusseted bags with four walls. In this way, not only space-saving stacking and shipping are provided but also a flat manufacturing procedure, for example, from a single film web that is joined with the oppositely positioned edges and sealed together in the longitudinal direction or a manufacturing procedure from strips which are joined in the width of the respective walls and then are sealed together by seams.

In the first case, in which first a hose shape of a single film web is produced, longitudinal seams at the circumference, aside from a single hose-forming seam, are not mandatory. At the same time, in particular the enlarged illustration according to FIG. 4 shows a willfully sealed-in longitudinal seam 12 between the side-gusseted wall 9 and the wider wall 7 which has been incorporated for reinforcement and contour shaping and requires no seal-tight sealing because the film at this location extends continuously without a cut and is provided only with a fixed reinforcement fold.

FIG. 5 shows the side-gusseted bag 1 in a folded state in which the wider walls 6 and 7 as main walls are laid flat and the side-gusseted walls 8, 9, 10, 11, folded in longitudinal direction approximately at half the width, are positioned there between. Since the main walls 6, 7 are wider than the side-gusseted walls 8, 9, 10,11 that among each other have the same width, the side-gusseted walls folded in half will not meet at the center but remain spaced apart continuously along the fold lines 21, 22 indicated in FIG. 6.

FIG. 6 shows the folded form of the side-gusseted bag 1 in a flat plan view with main surface 6 at the top whose parallel lateral edges 13, 14 extend in longitudinal direction according to arrow 15 in FIG. 1 and thereat are reinforced with parallel laterally projecting seams 15, 16. The seams 15, 16 converge toward the head seam 5 with slanted seams 17, 18 that, for a hexagon side-gusseted bag of the type considered here, can be seen on the outline of an approximately equilateral triangle. The bottom 3 forms in the folded form according to FIG. 5 and FIG. 6 also a triangular shape wherein a bottom seam 19 (without spout) provided to be congruent with the head seam 5 is provided for symmetry reasons so that parallel fold lines and congruent seams will result. The folded form according to 5 and 6 forms thus a “packet” with fold lines and seams that are stacked on each other. It is understood of course that willful modifications are possible indeed in order to displace, for example, the fold lines and the seams in the folded state relative to each other when this is preferred for better distribution of fold lines or seams.

The afore described embodiment of the type of a “drum” with flat bottom and head region is particularly in demand for applications in which such a side-gusseted bag as “inliner” is to be inserted into a more stable enclosing container of cardboard, wood or sheet metal that also can be filled well with a hexagon side-gusseted bag for providing a round cylindrical inner shape. Even a pentagon shape has already significant adaptation advantages relative to a conventional side-gusseted bag with four circumferential surfaces. On the other hand, it is apparent that, if desired, also a polygon form with more surfaces can be conceptualized and produced along the same lines.

Seams that are projecting outwardly like fins such as the seam 12 in FIG. 4 have been found to be advantageous not only for contour shaping of the fold lines and for reinforcement of the side-gusseted bag but also aid in preventing inner adhesion of the film of the side-gusseted bag in case of enclosing containers that have a smooth inner surface.

In FIG. 7 a variant of the side-gusseted bag is indicated as a whole at 22, in which two side-gusseted walls 23 and 24 illustrated in the drawing are shown with a fin seam 25 between each other and with fin seams 26, 27 relative to adjoining main walls (not illustrated), wherein the side-gusseted walls 23, 24 as well as the other side-gusseted walls and the main walls in a head region 28 and at a bottom 29 converge toward the center in a funnel shape. This is of interest in case of liquid-filled side-gusseted bags in particular in the head region 28 in order to facilitate complete filling and complete emptying. Such a bag is to be designed to be foldable in the same way to a flat state like the side-gusseted bag according to FIGS. 1 through 6 wherein only between the slanted seams such as the slanted seams 30, 31 elongate triangular end areas of the main walls and side-gusseted walls with narrower angles between the seams are provided. For these angles, again a head seam 32 is to provided into which a spout 33 is to be embedded from two sides in order to furnish the film of the side-gusseted bag with a solid injection-molded filling and pouring component. 

What is claimed is: 1.-10. (canceled)
 11. A side-gusseted bag comprised of film, the side-gusseted bag comprising: two main walls; side-gusseted walls circumferentially interposed between the main walls, wherein the side-gusseted walls are configured to be folded flat between the stacked main walls in a V-shape parallel to a longitudinal direction of the side-gusseted bag along fold lines; a spout arranged in a head region of the side-gusseted bag and fastened to the main walls; wherein the main walls are directly connected to each other in the head region by a head seam extending on opposed sides of the spout in a central area of the head region on either side of the spout and comprising a first end and a second opposite end; wherein between the main walls, at least on one longitudinal side of the side-gusseted bag, several of the side-gusseted walls are arranged; wherein, in the head region, the side-gusseted walls are connected to each other or to the main walls, respectively, by slanted seams that delimit the side-gusseted walls in the head region; wherein the slanted seams converge at a slant to the first end or the second opposite end of the head seam together with the fold lines of the side-gusseted walls that are appropriately spaced relative to each other.
 12. The side-gusseted bag according to claim 11, wherein the slanted seams, when the side-gusseted bag is folded flat, extend at an angle of less than 45° relative to the longitudinal direction.
 13. The side-gusseted bag according to claim 11, wherein the slanted seams are aligned relative to each other such that, when the side-gusseted bag is unfolded, the side-gusseted walls and the main walls form a planar surface in the head region.
 14. The side-gusseted bag according to claim 11, wherein, when the side-gusseted bag is unfolded, the side-gusseted walls and the main walls converge conically toward the head seam.
 15. The side-gusseted bag according to claim 11, wherein the side-gusseted walls all have the same circumferential width and the main walls have a circumferential width that is longer by a length of the head seam than the circumferential width of the side-gusseted walls.
 16. The side-gusseted bag according to claim 11, wherein the main walls and the side-gusseted walls are joined to each other by longitudinal seams, respectively.
 17. The side-gusseted bag according to claim 16, wherein the longitudinal seams are fin seams projecting outwardly away from the main walls and the side-gusseted walls.
 18. The side-gusseted bag according to claim 11, wherein the main walls and the side-gusseted walls in a bottom region of the side-gusseted bag opposite the head region are connected to each other with converging slanted seams.
 19. The side-gusseted bag according to claim 18, wherein, when the side-gusseted bag is unfolded, the side-gusseted walls and the main walls between the slanted seams supplement each other to a planar surface in the bottom region.
 20. The side-gusseted bag according to claim 11, wherein the film of the side-gusseted bag is a multi-layer composite film comprising a sealable layer arranged on an inner side of the side-gusseted bag. 